1. Field of the Invention
The invention relates, in general, to rotary engines and, in particular, to a new and useful adjustment device for the guide vanes of an axial-flow engine.
A similar adjustment of this nature is known from German Pat. No. 35 19 747. It permits changing the setting angle of the guide vanes during operation of the fluid flow engine, in particular of a turbo compressor and, in this way, adapting the response of the engine to varying operating conditions such as, for example, partial and full load, and to reduce losses of the degree of effectiveness.
In the prior known adjustment device, the adjustment ring is connected to the levers of the guide vanes through simple hinge bolts and is carried to them, hence, the ring is not guided separately on the housing. The articulation with the hinge bolts must have sufficient play, so that the adjustment motions, in which the adjustment ring and the levers rotate in different planes, is possible. The unavoidable heat expansion also presupposes sufficient play in the articulations.
During operation very strong forces act upon the guide vanes of a fluid flow engine. As far as they act perpendicular to the axis of the guide vane or parallel to it, they must be absorbed by the bearing of the guide vane shaft in the guide vane carrier. Additionally, however, strong torque occurs around the axis of the guide vane, which is transmitted over the levers to the adjustment ring. In this process, through the play in the articulation and through lacking guidance of the adjustment ring strong vibrations can be set up, which lead to losses of the degree of effectiveness and the operating life of the guide vane.
There are also adjustment devices for guide vanes known, in which the guide vanes are articulated through levers with an adjustment sleeve slidable in the axial direction, as, for example, according to German Pat. No. 31 25 639. Axially displaceable adjustment sleeves have the disadvantage that adjacent vane rings can only be adjusted in common, not, however, individually. Also, with respect to bearing play and sensitivity to vibration stresses similar problems occur. The known adjustment devices are provided in the low temperature range, in particular for compression, or the compression stage of open gas turbines. An adjustment device, which also can be satisfactorily applied in the high temperature range, in particular in closed gar turbines, is not known.